Ok so I'm building a box for my 93 silverado under the rear seat. Single 10" re audio sr pro sub. I'm looking to get very tight bass from it but still being able to get loud because of the ported design. I listen to punchy bass, rock, older rap. Dubstep, etc. so I need the kick drum bass from it. I'm not sure how to tune a port at all. I'm going round because if my box design. How should I go about size bs length on the port? Here's the sub specs.
Ive measure and I can get close to 1.2 to 1.3 cft under the rear seat on one side for the sub. I'm not going for extreme becausemim going to two subs down the round. I just need to get the box built for the one now. I already made a .55cft sealed box that my alpine type S is in but It doesn't get loud enough.

The sub will be recieving about 400 watts maybe 450 rms depending on how well it takes it. Re audio rep said that sub can handle that rms easily.

Here's a link to WinISD Beta (http://www.softpedia.com/get/Multimedia/Audio/Other-AUDIO-Tools/WinISD.shtml), which is no longer available from the author's site.

It's a simple to use modeling program that you can play with to find the tuning and box volume you like. I will also help you with port area and length and it has a cut sheet for simple boxes, although I've never used it.

Generally speaking though, you'll want tuning in the mid thirties to have good low end response and tight mid bass.